Tire expander



Dec. 29, 1936. w. G. LERCH Er AL 2,065,943

TIRE EXPANDER Y Filed Feb. 1, 1934 2 Sheets-Shet 2 Patented Dec. 29, 1936 UNITED STATES PATENT oFFlcE Findlay, Ohio, assignors to Master Tire and Rubber Corporation, Akron, Ohio, a corporation of Delaware Application February 1, 1934, Serial No. 709,315 .7,3

11 Claims.

'I'his invention relates to a mechanism for expanding tires which have been built on the at band process. As iswell known, tires which have been built on a drum, by the so-called pulleyband method have to be changed to the conventional horseshoe-shaped cross section.

' In particular the purpose of our invention is to perform this expansion by a relatively simple machine and in a manner which will not disrupt the tire structure. It is known, for example, to expand tire casings by vacuum, but this has an injurious eiect in sometimes pulling the treads and side wall portions of the tire loose from the carcass. This can be avoided by applying expansion pressure from inside, but a diilculty is here encountered in retaining the air pressure inside the tire during the expansion and applying expanding pressure uniformly.

The invention is particularly directed to means for retaining and applying the air pressure inside the tire and for permitting ready withdrawal of the tire from such expanding means.

As the tire expands, the beads approach one another, and it is one of the aims of the invention to apply expanding pressure while the beads are approaching. To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims.

The annexed drawings and the following description set forth in detail certain mechanism embodying the invention, such disclosed means constituting, however, but one of various mechanical forms in which the principle of the invention may be used.

In the accompanying drawings Fig. 1 is a view partly in section and partly in perspective showing our improved machine at the beginning of its operation, the section taken being central and vertical; Fig. 2 is a diagrammatic central vertical sectional view showing the parts in position before `the expansion begins, but with a diierent type of tire; Fig. 3 is a central vertical section showing the tire completely expanded; Fig. 4 is a side elevation of an apron usedA in the apparatus; and Fig. 5 is a top view of Fig. 4.

The tire expander in the preferred form here of vertical legs connected by horizontal rings 2. An upper disk 'or top plate 3 is hinged to this framework as shown and may be either lifted up r set down as in ition by any suitto open the top of the frame Figs. 2 and 3 and locked in able device such as the latch 4 shown in somewhat diagrammatic style. This upper disk 3 has a central opening 5 closable by a smaller lid 6 having suitable gaskets I and locking arrangements 8.

The machine also includes a lower disk or plat- 5 form II which may be raised by appropriate mechanism to any desired position. A motor I2 driving a threaded vertical shaft I3 is here indicated for that purpose.

As already stated, the action of the mecha- 10 nism is in general that a tire I5 in the flat band condition is placed on the lower disk I I as shown in Fig. l, the lid 3 is closed and the lower disk the tire casing, but is applied within a sleeve, or zo apron, as it is more generally known, I6. This apron is a hollow collapsible element which is preferably made of rubber of about the same thickness and resiliency as is used for inner tubes.

In the preferred form here shown the exterior 25 surface carries a number of ribs or strips I`I which may conveniently be strips of the same material cemented on. The apron I6 is fastened at the bottom to the lower plate II by any suitable means such as a'clamping ring I8, and at the top is fastened to a ring I9, known as the sealing ring.

The apron I6 may assume any one of a variety of forms as variously shown in Figs. 1, 2, 3 and 4. 'I'his feature will become clear as the operation of the apparatus is described below. The top plate 3 is equipped with a tire positioning ring or lip 20 surrounding the aperture 5 on the lower side and the bottom plate II is equipped with a ring 2| of the same diameter vertically therebelow on the bottom plate I I. venience the bottom plate II is here shown as built up higher outside of the ring 2l than inside of it. The ring 2|) has a plurality of lugs 22 adapted to be passed by apertures 23 in the ring I9 and to support the ring I9 when the latter is 45 slight] turned, -thus positioning the apron I6 in the shpe shown in Figs. 2 and4 at certain stages of the operation. Electromagnets 2l controlled by a switch 25 serve to lift the ring I9 oi the lugs 22 into air-tight contact with a gasket 26 on the 50 under side of the lid 6 before and during the application of air pressure inside the apron I6. Air is applied to the apron I6 through pipe 30 having a suitable inlet and exhaust valve 3l.

The rings 20 and 2l may be substituted in va- 55 As a matter of cono rious sizes according to the diameter of tires to be worked on, thus varying the capacity of the machine within reasonable limits. Ordinarily the resiliency of the apron is sufllcient for all sizes of tires which are within the capacity of any machine so that it is not usually necessary to change the apron and its rings Il and I9 for dinerent sizes, although this can be done if occasion arises. In running any particular size of tires the bottom plate is lowered away only to the height of the tire. Suitable automatic stops, not shown, can be provided so that in lowering the plate it will not go below the level necessary for the job in hand.

The cycle of operations is as follows. The lid 3 being raised sufliciently for the purpose and the lower. plate ti being at the proper height, the tire I5, in at band shape is placed in the machine with its lower' bead outside the ring 2|, as shown in Rig. 1. The lid I is then lowered and clamped down while the lid 6 is left open. The operator reaches in and takes the sealing ring Il by hand, lifts it from the position of Pig. 1 to that of Fig. 2 the openings 23 over the lugs 22 and giving thering i9 a slight twist so that it is held up by the lugs. He then closes -and clamps the lid 6, and closes the switch 25 so that the electmmagnets 2l are energized and bring the sealing 'ring il to air-tight engagement with the gasket 2l. At the same time the motor I2 is started and the air is admitted, somewhat gradually. through the valve 2|. Thus as the lower plate llrises, the apron is expanded and the operation ends with the parts in the positions shown in solid lines in Fig. 3. This position is held for a full minute or longer, thus allowing the elements of the tire II .to adjust themselves to the expanded position. Next the air is exhausted through the valve 3|. Due to an eirect which will be described below, thereupon the apron I6 assumes approximately the position I8'. The lid I is thenopened and the operator turns thesealingring iltoallowitto drop past the lugs 22 into the position of Fig. 1. Due to the reduced middle diameter of the apron it folds itself entirely inside the diameter of the rings I I and il as shown in Fig. 1 and is out of the way.

The subsequent steps are those common to any sort of tire expander and comprise the introduction of a curing bag, the opening of the large lid 3 and the removal of the tire, with the bag therein, for curing. 'Ihe bottom plate is then lowered for the next cycle of operations.

The action of the machine as a whole having been described, some further explanation of the action of the apron and oi the function of the strips I1 is necessary.

It has been found that the apron I8, if entirely smooth, has an objectionable tendency to stick to the inside of the tire I5. This can best be avoided by retaining a layer of air between the tire and the apron. The preferred arrangement for doing so comprises the use of the strips already described, which form air pockets and reduce the area of rubber-to-rubber contact between the apron and the tire. By reference to Fig. 2 it will be observed that there is a space, a cross section of, which is designated by the reference characterzf'A, between the apron and the tire before air pressure is applied. The air within this area is entrapped as the apron begins to expand and thus a layer of air, under some pressure, is maintained as the tire collapses to the position of Fig. 3. When the air within the apron is released by the valve 3|, as already mentioned, this entrapped air serves to force the apron to a position approximately represented by the dotted lines I6', Fig. 3, and escapes when the lid 6 is opened.

It will be understood that although strips Il are shown as the preferred form for accomplishing this result that it might be attained in any one of a variety of suitable ways.

Other modes of applying the principle of our invention may be employed instead of the one explained, change being made as Aregards the mechanism herein disclosed, provided the means stated by any of the following claims or the equivalent of such stated means be employed.

We therefore particularly point out and distinctly claim as our invention:

1. A tire expanding mechanism comprising upper and lower members movable towards one another, means on said members to guide the beads of an edgewise-disposed hat band tire standingv on the lower member without confining such beads. an apron carried by said members adapted to engage the inner surface oi.' said tire, means for applying air pressure within said apron, and means for causing said members to approach one another during such application of pressure.

2. A tire expander comprising a lower plate, an upper plate, a hollow flexible element secured to said lower plate, means for attaching said element to said upper plate, and additional means for bringing said element into air-tight contact with said upper plate.

3. In a tire expander having mutually approachable parallel upper and lower elements, a collapsible exible apron attachedV at one end in air-tight engagement to the lower of said elements and means for successively securing the other end of said apron first in non-air-tight and next in air-tight engagement to the upper of said elements.

4. In a tire expander having mutually approachable parallel upper and lower elements, a collapsible iiexible apron attached in air-tight engagement to the 'lower of said elements and attachable in air-tight\engagement to the upper of said elements, said apron, when extended, being of generally cylindrical form with reduced midsection, and means on the surface of said apron adapted to'form air spaces between said apron and a tire when said apron contacts a tire.

5. In a tire expander having mutually approachable parallel upper and lower elements,

a collapsible exlble apron attached in air-tight engagement to the lower of said elements and attachable in air-tight engagement to the upper of said elements, said apron, when extended, being of generally cylindrical form with reduced midsection, and irregularities on the surface or said apron.

6. In a tire expander having mutually approachable parallel upper and lower elements. a collapsible exible apron attached in air-tight engagement to the lower of said elements and attachable in air-tight engagement to the upper of said elements, said apron, when extended, being of generally cylindrical form with reduced mid section, said apron being smooth at upper and lower ends, and having a plurality of ribs on the portion between said ends.

7. A tire expander comprising a supporting frame, an upper plate movably attached thereto and movable into a horizontal position, a lower plate movable up and down in said frame, alignable positioning means on said upper and lower plates adapted to receive a flat band tire, an air-tight collapsible and expansible element juxtaposed within said positioning means on said bottom plate, a ring of magnetic material secured to the upper end of said collapsible element, a wall dening an opening through said top plate within said positioning means, elements, on said wall adapted to hold said ring, a door adapted to close saido opening, electro-magnets on said door adapted to move said ring into close engagement with said door, and means for moving said lower plate upward and for expanding said collapsible element.

8. In a. tire expander having mutually approachable parallel upper and lower elements, a collapsible flexible apron attached in air-tight engagement to the lower of said elements and attachable in air-tight engagement to the upper of said elements, said apron, when extended, being of generally cylindrical form with reduced mid section.

9. In a tire expander having mutually approachable par-allel elements, a collapsible flexible apron attached in air-tight engagement to one of said elements and attachable in air-tight engagement to the other of said elements, said apron, when extended, being of generally cylindrical form with reduced mid section.

10. In a tire expander having mutually approachable upper and lower elements, a collapsible flexible apron attachable in air-tight engagement between said elements, and irregularities on the outer surface of said apron.

1l. In a tire expander having mutually approachable upper and lower elements, a collapsible flexible apron adapted to extend between said elements and to be air-tight, and a plurality of raised members on the outer surface of said apron.

Y WILLIAM G. LERCH.

MURDEN T. BRYANT. 

